Rust removing composition



Patented July 23, 1940 UNITED STATES PATENT OFFICE 2,209,291 RUSTREMOVING COMPOSITION George Witty, Long Island City, N. Y., assignor,

by mesne Hartsdaie, N. Y.

assignments, to Frederick Le Pan,

No Drawing. Continuation of application Serial No. 140,707, May 4,

1937. This application November 23, 1938, Serial No. 241,955

2 Claims.

My invention relates to a new and useful composition for removing rust,scale, grease, oil and other foreign matter from metal surfaces and atthe same time will deposit a protective film which will prevent any newformation of corrosion and forming a bond for the finishing coats; suchas galvanizing, plating, painting, enameling or lacit attacks the cleanmetal itself, thereby causing' loss of metal, embrittlement, pitting,discoloration, and producing an evolution of hydrogen gas, which escapesinto the air, carrying with it a fine spray of the acid liquor from thepickling bath and creating an atmosphere possessing corrosive propertiesand one which is injurious to health and damaging to equipments.

There are great differences, between the hardness, brittleness. weight,tensile strength and other physical and chemical properties of thevarious metals, and in order to produce an efficient and economical rustremoving and rust g5; preventing compound and to eliminate the presentdifficulties, the following must be taken in consideration.

(i) The physical and chemical properties of the various metals.

(2) A solvent so balanced that it will remove the rust and prevent anyfurther formation of the same.

(3) The properties of the solvent must be capable of removing rust orany other deposit with- 40 out attacking the metal.

(4) To eliminate harmful fumes so it can be handled without risk ordanger.

(5) The most .suitable temperature must be maintained to facilitate thefunction of the sol- 45 vent.

The object of my invention is to provide a rust removing and rustpreventing medium, chemically balanced, that will economically and in a50 single operation, remove rust, scale, oil, grease and other depositsfrom the metal surfaces, without attacking the clean metal.

Another object of my invention is to provide a rust removing and rustpreventing compound 55 which will minimize the amount of metal lost incleaning or pickling operation, which will in-\ crease the efliciency ofthe pickling operation, and which will facilitate the cleaning orde-rusting operation without producing an atmosphere possessingcorrosive properties which are injurious to the health of workmen, anddamaging to the equipments.

A further object of my invention is to remove rust, scale, oil, greaseand materials that cause corrosion in a simple and eflective manner sothat when the work is completed the metal will be in condition suitablefor receiving a protective coating such as galvanizing, plating,painting, enameling or the like.

My improved composition is made from a liquid mixture of the followingingredients that are preferably used in the following proportions:

- Parts Anhydrous phosphoric acid 36 Zinc phosphate. 3 Gum ar 2Manganese chloride 1 Butyl prop 30 Water 28 All parts are by weight.

In preparing the composition,,the anhydrous phosphoric acid and zincphosphate are intermixed in an acid-proof tank with the butyl propionateto form a first batch. The gum arable and manganese chloride are placedin a mixing machine of any suitable type and dissolved in the water toform a second batch. The mixture is stirred until the gum arabic and themanganese chloride are thoroughly dissolved in the water.

The two batches are then thoroughly intermixed until a homogeneous massis formed. In some cases, additional water is added.

The composition may be applied to the metal surface by dipping,brushing, or spraying, after which the treated surface is washed withclean water and it is then ready to receive the finishing coat or coats.

While I have described in detail the preferred ingredients andproportions thereof, and also the preferred manner of compounding theingree clients so as to secure the most satisfactory composition for thepurpose. It is to be understood however, that the specific disclosure isfor the purpose of exemplification and that my invention in its broaderaspect is not limited either to the particular ingredients, proportionsor method of compounding specifically described but equivalent materialsmay be used, and the proportions and the method of compounding gumarabic produces an emulsion of the insoluble ingredients, and it mayemulsify the dissolved .oil, fat and grease. When a film of the'liquidis applied to the metal surface, the gum arabic maintains the film incontinuous form on the metal surface. Otherwise, the liquid would formseparate drops on the metal surface. Other substances could be usedinstead of the gum arabic. For example, it is well known that soaplowers the surface tension of water.

The zinc phosphate and the manganese chloride act as bufiers' when thephosphoric acid passivates the iron, steel and other metal surface. Theinvention is particularly useful in treating iron and its alloys, suchas steel, etc.

It will be noted that the composition is free from any acid which isstronger than phosphoric acid.

Such stronger acids include nitric acid, hydrochloric acid, andsulphuric acid.

The zinc phosphate is insoluble in water, but it is soluble inphosphoric acid.

This application is a continuation of my former application, Serial No.140,707, filed May 4, 1937, forfeited March .1, 1938.

Since zinc is more electropositive than iron,

.I prefer to use a zinc salt in the composition,

when it is used for cleansing and rust-proofing iron. The zinc phosphateis the tribasic salt Zna(PO4)2.4H2O.'

Having described my invention, I claim:

1. A rust removing composition, comprising phosphoric acid, zincphosphate, gum arabic, manganese chloride, butyl propionate and water.

2. A rust removing composition, comprising .phosphoric acid 36 parts,zinc phosphate 3 parts,

gum arabic 2 parts, manganese chloride 1 part, butyl propionate 30 partsand water 28 parts, said proportions being by weight.

GEORGE WI'I'I'Y.

